I know this has probably been asked before, but I've searched the web and found mostly unsatisfying answers (on other forums, of course): When is it preferable to use multiband compression instead of / or to enhance EQ? 

 (So at the conceptual level I understand the differences between the two, but it's the when, why (or why not), that I'm trying to understand.  MB Compression seems like such a powerful tool, but perhaps one only to be use with great discretion... which means I've probably blown it by using it on individual tracks.)

Part of the answer involves consideration of whether you are using significant make up gain on any particular band you are compressing.

edit to add: You may use the Multiband to change the texture of a bandpass range while using make up gain to make sure you do not change the apparent amplitude.

I don't have an answer that will serve as a guide line, but I think that the statement above might highlight some potential differences in how you might find that multi band compression can be significantly different than EQ.

best regards,
mike






edited

Thanks Mike.
I read something about "spectrum smearing" at the cross-over points as a reason not to use multi-band compression, but not really sure what that means.

If that is a concern, you can always just use one band of the multiband... and then perhaps use an additional regular full spectrum compressor in series for generalized duty.


Most EQs have the potential for over lap issues as well.

It's probably more often something to be aware of and less often something to be concerned about.

I think the problem might show up if you were using the multiband as a creative and dramatic filter, like in a synth patch, but it will be unlikely to cause any discernible problem if you are using the multi band to simply control some bandpass range with a mild setting.

best regards,
mike

Multiband comps can help you tighten up or fatten up the low end (for instance) while leaving the high end alone.  It can be used to dramatically effect the EQ but I believe it is a tool more intended & useful as a problem solver than something to just throw on every track.

i think if you have a need for multiband compression, then you have a need to go back and fix your mix.


EQ is preferable to me.

now, that's not to say that you wont end up with a source that absolutely has to be tamed, and for this, it's good to know how to use a MB


but for material you have control over tracking, there really should not be a need for multi band compression, IF you have done your job throughout tracking.

I do not think its a question of EQ vs Multi-band compression.  I think its a question of, "when to use eq, when to use compression, when to use multi-band compression, and when to chain these things up."

Warning!  This is not encyclopedic quality writing below.  You can verify the veracity of my knowledge through books and google, but I am not going to fact check what I am about to say..  I am just writing from my head..




To simplify Eq, Compression, and Multi-band Compression

Eq's are processor that use filters to cut and boost frequency.  Compressors are processors that work to control volume.  Multi-band compressors split frequency and therefore compress on a certain band of frequency.

When you use a processor in a mix, you are doing so to A.  Balance the track.  B.  Shape a certain sound and vibe.  I can't think of any other goals to mix music...

Example: You balance volume and panning of a guitar, and you add a phaser for a cool vibe..  You balance the bass frequency, and you may have a four bar bass filter sweep for a cool vibe...

Multi-band compression is not a processor that would go everywhere.  Same as compression and eq are not processors that need to go everywhere...  "Although, I am using a huge amount of compression, years ago I had other producers on the forum complaining that my tracks where too dynamic for dance music..."  Compression seems to be, "the sound," at this point.

Multi-band compression..  I usually use it during my mastering stage.  I usually use multi-band, "hand in hand," with eq.  One does not replace or negate the other, in my productions...

Lately, I have been searching for more clever ways to use multi-band in my mixing, and create more of a, "sound via multi-band."  I am in the very early stages of this, but I would say, "yep, I would use discretion.  Nope, I do not thing it negates, or replaces eq."

Some sounds need eq, some sounds need compression, some sounds need eq and compression, some sounds do not need eq or compression, some mixing scenarios would sound great with multi-band, some multi-band techniques are best reserved for mastering...

I use it sparingly as a tool to control certain things that are getting out of control.  Here is an example:

On a lead guitar part - Let's say I'm using the Neck pickup and riffing up high - nice creamy lead, but during the phrase I go to the low strings briefly (without switching pickups) and hit some low notes.  All of a sudden I'm producing too much energy around 200hz.  I don't compress my lead guitar because the amp is a naturally compressor.  But in this case I have to tame that 200hz. - So I add the MB compressor and only activate compression in that frequency range.  Works perfect.

I use an EQ to sculpt the tone I want - it is active all the time on a specific track.

Summary - I use MB compressor sparingly as a tool.  It can come in handy at times.

Thanks all. Good advice all around. I honestly became aware of MB compressors when trying to do some de-essing and got, perhaps, overly enamored by the power of the tool. Thanks again for your help and insights; you all are a wealth of knowledge.

jhughs


I know this has probably been asked before, but I've searched the web and found mostly unsatisfying answers (on other forums, of course): When is it preferable to use multiband compression instead of / or to enhance EQ? 

(So at the conceptual level I understand the differences between the two, but it's the when, why (or why not), that I'm trying to understand.  MB Compression seems like such a powerful tool, but perhaps one only to be use with great discretion... which means I've probably blown it by using it on individual tracks.)

Great answers from everyone so far. I'll add my experience using these if I may?
 
I'm in the camp that you try your best not to use these if you can help it. They seriously can do more harm than good if you're not careful. But if you DO need to use them, I'll give you a few examples to where a tool like this can be extremely helpful.
 
Problematic Bass guitar: Ever deal with one of those 5-string basses with the low B? That low B is going to come in somewhere around the 31 Hz range. Now that doesn't mean you just grab the MBC, select 31 Hz and start adding threshold. Hahaha!
 
There are lots of things that factor in with where you should go with this. Just because a low B resonates at 31 Hz doesn't mean you will hear excessive 31 Hz on your project. You'll need to scope where the problem is coming from as well as how often it appears. Most times you get a little more exaggerated playing on the open notes and sometimes pups need adjustment. So you may get more push when the guy plays that open B. You'll notice that the other notes he plays sound fine, but when that B hits, you hear it all over the place.
 
You of course could automate your volume, but you will notice the low B gives you a slightly different timbre than the other notes he plays. What I personally like to do is split the clip where this happens and run a dedicated eq on this section while using a MBC to tighten it up. Once you know where the offending frequency is, you can just use the MBC to police the area in that range so that the low B doesn't jump out of its cage. This will tighten it up and also help to uniform the sound of the bass with the other notes. It can also compensate for lower/higher action on that string as well as a pup that may be too high making the note lash out more than the others.
 
High Gain Rock Guitar: Whenever we have high gain guitar, we're bound to have loads of gain artifacts and what I call "whoomfing bass low end". Sometimes high passing is just not enough or may affect the sound too much to where it loses impact. This is where a multiband compressor can make a nice difference. When you use a guitar sound like this and chug on certain chords, it will ramp up your LED meters. You'll notice chugging on a low E will give you one reading on your meter while chugging on an A will give you another reading which will be higher. Ab's, A, Bb and B will always ramp up your meter a little more. Add high gain and how guitar players love low end into the mix and this can make a bad guitar sound....sound even worse....or a good guitar sound...sound bad.
 
After you high pass and find the sweet spot, you may still notice some ramping up on certain chords to where they sound un-even. A regular compressor will squash the sound here where a MBC will just grab the frequency and compress it. This is what we want in this situation. A did a Billy Idol cover a few years back where every time I played a certain chord structure, 120 Hz would ramp up and sound strange. Nothing I tried fixed it...and what sucked was, all the other chords sounded great. So I split my clips, threw the MBC on, set it up for 120 Hz and each time that passage came, it just tamed the 120 in it that would ramp up...not the entire guitar tone. So this is where these things can really work well because they work on controlling the frequencies in this instance more than the entire instrument. The key is not to over-use this and if you can split a clip to where you just target the area that is in need of help, it's a no lose situation every time.
 
Mastering: I really love a good MBC in my mastering chain, but never to the extreme. You definitely don't want to use these in place of an eq or in place of a compressor. What I do in the mastering stage with this is as follows...
 
I set up my mastering chain with what I feel is best for the particular project I'm working on. This usually consists of quite a few eq's and a really good compressor. From there when I get things the way I want them, I use the MBC lightly to police the master I've created. It's sort of like a fine tuner but it will barely kick in unless something gets a little out of line. In this scenario I'm pretty much using it as polish so to speak. You know...sort of like a glue effect that is also keeping things tight without showing itself to where it can be heard. Like the fine tuners on a locking nut....we have the mix tuned up and sounding good, this just makes sure things stay that way. It can tighten up your sub lows, smooth out mids or clamp them slightly to control mid-range congestion and of course control how your high end comes across. But the key is moderation at this point because we don't want to ruin the great master we have created. I call my MBC in the mastering stage, "My Border Patrol". And all it does is stop certain frequencies from crossing that line.
 
But yeah, you shouldn't ever have to use these on every track like you've been doing. You'll wind up getting a bunch of pumping artifacts, inconsistencies and weird frequency behavior. Everything in moderation....but definitely get your mix the best you can and try not to use these if you can help it. Good luck. :)
 
-Danny